[commit: ghc] master: Improve error messages for ambiguous type variables (7b443bb)

Thu Oct 8 01:28:12 UTC 2015

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/7b443bb1df8f7f0a6b3124537590aa655a9300cd/ghc

>---------------------------------------------------------------

commit 7b443bb1df8f7f0a6b3124537590aa655a9300cd
Author: David Kraeutmann <kane at kane.cx>
Date:   Wed Oct 7 20:28:46 2015 -0500

    Improve error messages for ambiguous type variables

    Improved error messages are only printed when the old message would be
    "No instance for...", since they're not as helpful for "Could not deduce..."

    No special test case as error messages are tested by other tests already.

    Signed-off-by: David Kraeutmann <kane at kane.cx>

    Reviewed By: austin, goldfire

    Differential Revision: https://phabricator.haskell.org/D1182

    GHC Trac Issues: #10733

>---------------------------------------------------------------

7b443bb1df8f7f0a6b3124537590aa655a9300cd
 compiler/typecheck/TcErrors.hs                     | 95 +++++++++++++++++-----
 .../tests/annotations/should_fail/annfail10.stderr | 14 ++--
 .../tests/ghci.debugger/scripts/break006.stderr    |  4 +-
 .../tests/ghci.debugger/scripts/print019.stderr    |  2 +-
 testsuite/tests/ghci/scripts/Defer02.stderr        |  7 +-
 .../tests/indexed-types/should_fail/T4485.stderr   |  7 +-
 .../should_fail/overloadedlistsfail01.stderr       | 21 +++--
 testsuite/tests/quotes/TH_localname.stderr         |  7 +-
 testsuite/tests/rebindable/rebindable6.stderr      | 26 +++---
 testsuite/tests/rename/should_fail/mc14.stderr     |  8 +-
 .../tests/typecheck/should_compile/holes2.stderr   |  7 +-
 testsuite/tests/typecheck/should_fail/T4921.stderr | 14 ++--
 testsuite/tests/typecheck/should_fail/T5858.stderr |  9 +-
 testsuite/tests/typecheck/should_fail/T7857.stderr |  2 +-
 .../tests/typecheck/should_fail/tcfail008.stderr   |  7 +-
 .../tests/typecheck/should_fail/tcfail040.stderr   |  7 +-
 .../tests/typecheck/should_fail/tcfail043.stderr   | 14 ++--
 .../tests/typecheck/should_fail/tcfail072.stderr   |  2 +-
 .../tests/typecheck/should_fail/tcfail128.stderr   |  9 +-
 .../tests/typecheck/should_fail/tcfail133.stderr   |  7 +-
 .../tests/typecheck/should_fail/tcfail181.stderr   |  2 +-
 21 files changed, 173 insertions(+), 98 deletions(-)

Diff suppressed because of size. To see it, use:

    git diff-tree --root --patch-with-stat --no-color --find-copies-harder --ignore-space-at-eol --cc 7b443bb1df8f7f0a6b3124537590aa655a9300cd